This invention relates to a run-on lining (also known as a blade tip seal insert) for the housing of a turbo-engine and, more particularly, to a lining constructed as a ring-type carpet on the circumference of the housing opposite the moving blades of a turbo-rotor, and including a carrier in which ceramic fibers are held, the free fiber ends projecting radially toward the inside out of the carrier. The invention further relates to a process for manufacturing such a run-on lining.
Run-on linings are arranged between the free ends of moving blades and a housing of a compressor or of a turbine of a turbo-engine. During the operation of such engines, the run-on linings are subjected to high specific stresses.
There is therefore needed a run-on lining for turbo-engines which is reasonable in cost, simple to manufacture, efficient and resistant to wear. There is also needed a process for mounting such run-on linings for turbo-engines.
These needs are met according to the present invention by a run-on lining for turbo-engines constructed as a ring-type carpet on the circumference of the housing opposite the moving blades of a turbo-rotor, and including a carrier in which ceramic fibers are held, the free fiber ends projecting out of the carrier radially toward the inside. The carrier is a SiC fabric mat having fabric strands which essentially cross one another at right angles. The ceramic fibers in the respective nodal points wind around both mutually crossing fabric strands while forming an apex.
A process for manufacturing such a run-on lining for turbo-engines includes the steps of: a) placing fiber bundles in a carrier such that the fiber bundles are directed via their free ends radially toward the inside; b) fastening the fiber bundles in the carrier; and c) fastening the carrier in the housing.
The run-on lining according to the present invention for turbo-engines may be prefabricated outside the housing from simple and cost-effective elements, such as a carrier and fiber bundles made of SiC-loops, and may subsequently be fastened in the housing. The alignment of the fiber ends of the fiber bundles on moving blades results in an effective sealing-off of the moving blades without any significant rotational impairment of the moving blades. The run-on lining for turbo-engines according to the invention is very wear resistant.
German Patent document DE 43 10 104 A1 describes a lining on the interior side of a turbo-engine housing. The lining is constructed as a ring-type carpet on the circumference opposite moving blades of a rotor. From the previously known German Patent document DE 36 06 283 A1, a brush seal is known for sealing off circumferential gaps. The brush seal is made of silicium carbide fibers. Ceramic fibers are used as the bristle material for the brush seal. However, these known references do not contain any information concerning a run-on lining made completely of ceramic material, or its design so that it can be produced at low cost.
For improving the accommodation and the durability of the run-on lining for turbo-engines, the housing of the turbo-engine, according to an advantageous embodiment of the invention, is provided with one or several grooves extending in the circumferential direction.
The mounting of the run-on lining according to the invention in one piece or in sections allows for specific conditions of the turbo-engine to be taken into account.
According to the present invention, a process for manufacturing run-on linings for turbo-engines is also provided by which the run-on lining for turbo-engines can be worked particularly advantageously into housings of turbo-engines.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.